Electric switch



Sept. 17, 192 9. J. D. HlLLlARD ELEGTiiIC SWITCH Fil ed April 30, 1925FL I.

To Compressed /Air Sup ail; J

' Inventor John D.HLLLLC1PCL M 4v HLs Attorney Patented Sept. 17, 1929UNITED STATES PATENT OFFICE- JOHN D. mLLIAnn, F SCHENEC'iADY, new YORK,ASSIGNOB T0 GENERAL ELECTRIC COMPANY, A CORPORATION on NEW YORK ELECTRICSWITCH Application filed A ril 30, 1925. Serial No. 21,007.

My invention relates to electric switchesot the fluid break type and.particularly to switches of this type in which the circuit is broken bythe downward movement of a movable contact. One object of my inventionis to provide an improved construction of switch of this nature which isadapted for use in high tension service, has a large interruptingcapacity and which requires the use of but a single insulating bushing.Another object is the provisionof means wherebythe movable contact canbe completely withdrawn fron the bottom of the fluid tank and replacedif desired 'without disturbing the tank or withdrawing the fluidtherefrom.

My invention will be better understood il'rom the following descriptiontaken in com 'nection with the accompanying drawing, and its scope willbe pointed out in'the appended claims.

Referring to the drawing, Fig. 1 is a vertical sectional View of a fluidbreakswitch illustrating my invention, and Fig. 2 is afragmentary viewillustrating a modification.

From 'a suitable supporting structure 1 wvhich, for example, maycomprise structural steelmembers, are shown depending a plurality ofsuspension insulators 2 of a type employed for supporting transmissionlines, etc. The cover 3 oft-he switch tank 4 is supported by theinsulators ":2 whence the tank is effectively insulated from thesupporting structure 1. The tank 4 has a detachable bottom as shown andis secured to thecover in any desired manner but preferably by weld-iing. The inner shell 5 is secured at the top to the cover 3 alsopreferably by welding and being open at thebottom forms'with the tank 4a cushioning air space 6. The tank is otherwise filled with insulatingfluid 7, as for example oil, and is provided in the cover with a floatactuated valve 8 which operates automatically to release gases producedby the are drawn in the insulating fluid'upon the separation of thecontacts. j

The switch according to'the embodiment of my invention illustrated isadapted to break the circuit at a single pointand accordingly has butone stationary contact and one movable contact. The singlestationary-contact 9 is carried by the inner end of the insulatorbushing 10 which is mounted in the cover 3, a circuit terminal 12 beingsecured to the outer end of the bushing. The movable contact rod 13 isreciprocally mounted in the bottom of the tank 4 and is electricallyconnected therewith hence the other circuit terminal of the switch. mayif desired beattached directly to the tank as shown for example at H. Aplate 15 having a suitable stufliug box 16 for the rod 13 is secured tothe bottom of the tank so as to cover the enlarged opening therein.Tightly secured tothe inner face of the bottom of the tank is a. cap 17through the crown of which is an opening for the free passage of thecontact rod 13. This rod 13. by means hereinafter described. is adaptedto be completely withdrawn from the tank for purposes of inspection.repair or re-, placement and in order to prey'eut the escape ofinsulating fluid at such times a flap door 20 is provided. This door hasa suitable gasket on its face so as to seal the opening in the cap toprevent the escape of oil and is mounted on a short shaft journalled inthe cap 17.

Tlie door is opened and closed by the hand -wheel 21" on the secondshaft- .22 which ex-' tends through the tank and which is connect ed bygearing 23 with the shaft carrying the (1001'. For the purpose ofinsuring good contactbetwe'en the tank 4 and the rod 13 I have shown a.spring-pressed contact member 24 which preferably is segmental in form.the

segments being pressed against the rod by helical or by garter springsto insure good contact at all times with the rod.

For supporting the contact rod operating mechanism a stool 26 isprovided having its legs bolted to the undr side of the tank bottom.The'openings between the legs facilitate accessto the stuffing box 16 aswell as access to thebolts securing the plate 15 to the tank bottom. Thecylinder 27 depends from the stool 26 and has the piston 28 mounted onthe lower end of the rod 13. the latter passing through the stufiing box29." The'bottom of the cylinder is closed by end head 39 which isreadily detachable to permit the with 'drawal of the piston and contactrod. Air

pressure is preferably employed for operating box 16 and contact 24 mayalso then be removed.

I anismin addition to air supply through ing the movable contact rodandacco rding to the illustration, opposite ends of the cylinder areconnected to a source of compressed the slide valve 40. The operatinghandle 41 of this valve may be operated manually or otherwise asdesired. and may have an insulation section 42 interposed at some pointtherein. I

The operation of the contact operating means whereby the circuit isopened and closed will be obvious from the drawing, andthe descriptiongiven above. H Should'the con'tactrod 13 become burned or should onedesire to inspect this rod or the contact member 24, the rod is firstmoved to openiposition in which position the upper end of the rod stillprojects above the end of the cap 17. By removing the bottom cap 39 ofthe cylinder the piston 28 can be lowered until the end of the rod 13 isbelow the top of the cap 17.

Handle 21 is then rotated to close the door 20. tightly after which thepiston and rod may be completely'removed. If desired, the stud-Furthermore, with the door 20 in its closed position the entireoperating mechthe contact rod may be removed and subsequently replacedwithout the removal or the loss of the insulating fluid.

of, a fixed :contact mounted in the tank, iJcooperating contact rodmounted to slide 7 said opening, means external to the tank for movingthe rod into and out of engagement with the fixed contact, said rod eingadapted to be com letely removed through said opening from the tank, avalve mounted within the tank, and means operable from the exteriorofthe tank for moving the valve to a position completely closing saidopening to prevent the escape of liquid when the rod is removed. A

In witness whereoffl have hereunto set my hand this 29th day of April,1925. 1

JOHN D. HTLLIARD.

In the modified form shown in Fig. 2 the inner shell 5 and the floatactuated valve 8 are omitted, and an expansion space is maintainedbetween the cover 3; and the level of the insulating fluid. Theinsulating bushing 44' is somewhat longer in this case and sur--rounding that portion of the bushing which extends through the space' isa metal ground shield 45. The mechanism for operating the movablecontact and for closing the opening iIp the bottom of the tank is thesame as in ig. 1. While I have described only one embodi ment ofmyinvention, I do not wish to be limited to the particular form shownand de-. scribedas it will be apparent that many modifications thereinmay be made without departing from the scope of my invention as setforth in the appended clanns.

What I claim as new and desire to secure by Letters Patent ofthe UnitedStates, is 2-- j 1. An electric switch comprising. a tank containinginsulating liquid and having an opening in the bottom thereof, a fixedcon tact-mounted in the tank, a cooperating mov-y.

able contact rod mounted to slide insaid opening, said rod being adaptedto be completely removed through said opening from the tank, and a valvesupported by the tank and arranged to be moved to a position completelyclosing the opening therein when the rod is removed'therefrom.

2. An electric switch comprising a tank 1 containing insulating liquidand having an opening in the bottom thereof, insulators supporting saidtank from the top there-

